Cashier's checks are deposited similar to a personal check or money order. You'll endorse the check and take it to the financial institution where you do your banking and ask for the funds to be credited to your account. Depending on your bank, you may need to bring your bank card or photo ID as well. While the funds in a cashier's check are the issuing bank's, and therefore ostensibly more secure, the proliferation of forged cashier's checks means you might not have instant access to the money.
If it's inconvenient to deposit the cashier's check with a teller, you have several other options. You also can deposit it at an ATM by endorsing the check and submitting it as instructed. If your bank offers deposit using a smartphone, you'll be able to deposit it using that device as well. Simply take a picture of the front and back of the check and submit it using the app your bank provides.
People who buy cashier's checks have to provide the money at the point of purchase. The bank then moves the funds into one of its own accounts and issues a check signed by the cashier, allowing the recipient to draw on the bank's funds for payment. Because it's a more reliable form of payment than a personal check, you'll usually have up to $5,000 of the funds available the next business day if you present the check to a teller for deposit. If you use an electronic option, you may have to wait another day or two.